JPH08-011761 A published by the Japan Patent Office in 1996 discloses a steering damper for suppressing unintended yaw or yaw oscillation of a front wheel and handlebars of a motorcycle due to shimmy or kickback during travel.
The steering damper is constituted by a double-rod type linear damper having a pair of piston rods fixed to both ends of a piston accommodated in a cylinder so as to be free to slide. The pair of piston rods project axially from the cylinder. Resistance against axial displacement of the piston in the cylinder can be adjusted from outside.
The cylinder is connected to a vehicle body of the motorcycle and one of the pair of the piston rods is connected to the handlebars at a location offset from a steering center of the handlebars.
When the handlebars are turned, the cylinder and the piston rod connected to the handlebars contract or elongate in an axial direction causing the piston to displace axially in the cylinder. Two oil chambers are separated in the cylinder by the piston, and working oil moves between the two oil chambers via an orifice according to the displacement of the piston in the cylinder. A flow resistance of working oil through the orifice brings about a damping force that damps yaw of the front wheel and the handlebars.